Brake slip-controlled hydraulic brake system, especially for use with automotive vehicles

Abstract

An anti-locking, hydraulic brake system is described comprising a master cylinder (4), a pressure fluid collector, at least one wheel brake (5) which, through a master pressure conduit (7), is in communication with the master cylinder (4) and, through a return conduit (12), is in communication with an auxiliary pressure pump (8), an electromagnetically actuated outlet valve (13) in the return conduit (12), and a hydraulically controlled inlet valve (6) in the master pressure conduit (7). The pump is connected to the wheel brake by an auxiliary pressure conduit having a throttle restriction therein. A control conduit branching from the auxiliary pressure conduit upstream from the throttle restriction operates the inlet valve. A diaphragm valve (3) allows either unrestricted or restricted communication of the master cylinder with the master cylinder pressure conduit, the diaphragm valve hydraulically re-switchable by a differential pressure exterted through a first control conduit (1) and a second control conduit (2) provided between the inlet valve (6) in the master pressure conduit (7) and the master cylinder (4).

I claim: 
     
       1. An anti-locking hydraulic brake system for an automotive vehicle, comprising: a master cylinder; at least one wheel brake, a master cylinder pressure conduit communicating said wheel brake with said master cylinder; a pressure fluid collector; a return conduit in communication with said wheel brake and said pressure fluid collector; an electromagnetically actuated outlet valve in said return conduit, said outlet valve in a resting position blocking said return conduit, and, in an actuated switching position, opening said return conduit; a hydraulically controlled inlet valve in said master pressure conduit; an auxiliary pressure pump having an intake taking in pressure fluid from said pressure fluid collector and having an outlet; an auxiliary pressure conduit feeding pressure fluid from said auxiliary pressure pump outlet directly to said wheel brake whenever said auxiliary pressure pump is operated; a control conduit branching from said auxiliary pressure conduit to said inlet valve to operate said inlet valve; a throttle restriction in said auxiliary pressure conduit downstream from said control conduit branching; said pump outlet constantly connected to said wheel brake whenever said auxiliary pressure pump is operated to pressurize said outlet, said throttle restriction the only element in said auxiliary pressure conduit affecting outflow from said pump outlet to said wheel brake; a diaphragm valve in said master cylinder pressure conduit upstream from said inlet valve, hydraulically shiftable from a first condition allowing substantially unrestricted flow from said master cylinder to a second condition allowing only restricted flow from said master cylinder by means responsive to a predetermined pressure difference thereacross in said master cylinder pressure conduit. 
     
     
       2. A brake system according to claim 1, wherein said means responsive to a predetermine pressure difference includes a first control conduit connected to said diaphragm valve and said master pressure conduit to branch off between said master cylinder and said diaphragm valve, and a second control conduit connected to said diaphragm valve and to said master pressure conduit between said inlet valve and said diaphragm valve. 
     
     
       3. A brake system according to claim 1, wherein said pressure fluid accumulator is disposed, in shunt, in said return conduit between said outlet valve and said auxiliary pressure pump. 
     
     
       4. A brake system according to claim 1, wherein said auxiliary pressure conduit in communication with said auxiliary pressure pump terminates in said master pressure conduit between said inlet valve and said wheel brake.